Today, there are still about 1.4 million allotment gardens in Germany covering an area of 470 km2

Allotment gardens are characterised by a concentration in one place of a few or up to several hundreds of land parcels that are assigned to individuals or families. In allotment gardens, the parcels are cultivated individually, contrary to other community garden types where the entire area is tended collectively by a group of people.

The individual size of a parcel generally ranges between 50 and 400 square meters, and often the plots include a shed for tools and shelter. The individual gardeners are usually organised in an allotment association which leases the land from an owner who may be a public, private or ecclesiastical entity, and who usually stipulates that it is only used for gardening (i.e. growing vegetables, fruits and flowers), but not for residential purposes (this is usually also required by zoning laws).

The aspect of food security provided by allotment gardens became particularly evident during World Wars I and II. The socio-economic situation was very miserable, particularly as regards the nutritional status of urban residents. Many cities were isolated from their rural hinterlands and agricultural products did not reach the city markets anymore or were sold at very high prices at the black markets. Consequently, food production within the city, especially fruit and vegetable production in home gardens and allotment gardens, became essential for survival.

The importance of allotment gardens for food security was so obvious that in 1919, one year after the end of World War I, the first legislation for allotment gardening in Germany was passed. The so-called "Small Garden and Small-Rent Land Law", provided security in land tenure and fixed leasing fees. In 1983, this law was amended by the "Federal Allotment Gardens Act"

Nevertheless, the importance of allotment gardening in Germany has shifted over the years. While in times of crisis and widespread poverty (from 1850 to 1950), allotment gardening was a part time job, and its main importance was to enhance food security and improve food supply, its present functions have to be seen under a different point of view.

In times of busy working days and the hectic urban atmosphere, allotment gardens have turned into recreational areas and locations for social gatherings. As green oases within oceans of asphalt and cement, they are substantially contributing to the conservation of nature within cities.

The Office International du Coin de Terre et des Jardins Familiaux, a Luxembourg-based organization representing three million European allotment gardeners since 1926, describes the socio-cultural and economic functions of allotment gardens as follows:

• for the community a better quality of urban life through the reduction of noise, the binding of dust, the establishment of open green spaces in densely populated areas;
• for the environment the conservation of biotopes and the creation of linked biotopes;
• for families a meaningful leisure activity and the personal experience of sowing, growing, cultivating and harvesting healthy vegetables amidst high-rise buildings and the concrete jungle;
• for children and adolescents a place to play, communicate and to discover nature and its wonders;
• for working people relaxation from the stress of work;
• for the unemployed the feeling of being useful and not excluded as well as a supply of fresh vegetables at minimum cost;
• for immigrant families a possibility of communication and better integration in their host country;
• for disabled persons a place enabling them to participate in social life, to establish contacts and overcome loneliness;
• for senior citizens a place of communication with persons having the same interests as well as an opportunity of self-fulfillment during the period of retirement. 

Immigrant families living in Germany can easly have their own KGA?

http://www.gesetze-im-internet.de/bkleingg/index.html